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  • 内核链表list.h

    stddef.h

    #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)

    list.h

    #ifndef _LINUX_LIST_H
    #define _LINUX_LIST_H

    #include <linux/stddef.h>
    #include <linux/poison.h>
    #include <linux/prefetch.h>
    #include <asm/system.h>

    /*
    * Simple doubly linked list implementation.
    *
    * Some of the internal functions ("__xxx") are useful when
    * manipulating whole lists rather than single entries, as
    * sometimes we already know the next/prev entries and we can
    * generate better code by using them directly rather than
    * using the generic single-entry routines.
    */

    struct list_head {
        struct list_head *next, *prev;
    };

    #define LIST_HEAD_INIT(name) { &(name), &(name) }

    示例:

    struct fox red_fox = {
        .tail_length = 40,
        .weight = 6,
        .list = LIST_HEAD_INIT(red_fox.list);
    };

    #define LIST_HEAD(name)
        struct list_head name = LIST_HEAD_INIT(name)

    示例:

    LIST_HEAD(head);

    static inline void INIT_LIST_HEAD(struct list_head *list)
    {
        list->next = list;
        list->prev = list;
    }

    示例:

       1:  struct fox{
       2:      unsigned long tail_length;
       3:      unsigned long weight;
       4:      bool          is_fantastic;
       5:      struct list_head list;
       6:  };
       7:   
       8:   
       9:  struct fox *red_fox;
      10:  red_fox = kmalloc(sizeof(*red_fox), GFP_KERNEL);
      11:  red_fox->tail_length = 40;
      12:  red_fox->weight = 6;
      13:  red_fox->is_fantastic = false;
      14:  INIT_LIST_HEAD(&red_fox->list);

    /*
    * Insert a new entry between two known consecutive entries.
    *
    * This is only for internal list manipulation where we know
    * the prev/next entries already!
    */
    #ifndef CONFIG_DEBUG_LIST

    将new查到prev和next中间
    static inline void __list_add(struct list_head *new,
                      struct list_head *prev,
                      struct list_head *next)
    {
        next->prev = new;
        new->next = next;
        new->prev = prev;
        prev->next = new;
    }

    #else
    extern void __list_add(struct list_head *new,
                      struct list_head *prev,
                      struct list_head *next);
    #endif

    /**
    * list_add - add a new entry
    * @new: new entry to be added
    * @head: list head to add it after
    *
    * Insert a new entry after the specified head.
    * This is good for implementing stacks.
    */

    image

    将new插入的head后面。
    static inline void list_add(struct list_head *new, struct list_head *head)
    {
        __list_add(new, head, head->next);
    }


    /**
    * list_add_tail - add a new entry
    * @new: new entry to be added
    * @head: list head to add it before
    *
    * Insert a new entry before the specified head.
    * This is useful for implementing queues.
    */

    image

    将new插入到head前面
    static inline void list_add_tail(struct list_head *new, struct list_head *head)
    {
        __list_add(new, head->prev, head);
    }

    /*
    * Delete a list entry by making the prev/next entries
    * point to each other.
    *
    * This is only for internal list manipulation where we know
    * the prev/next entries already!
    */

    删除prev和next中间的结点
    static inline void __list_del(struct list_head * prev, struct list_head * next)
    {
        next->prev = prev;
        prev->next = next;
    }

    /**
    * list_del - deletes entry from list.
    * @entry: the element to delete from the list.
    * Note: list_empty() on entry does not return true after this, the entry is
    * in an undefined state.
    */

    从链表中删除entry所在的结点,不释放entry的空间

    #define LIST_POISON1  ((void *) 0x00100100)
      #define LIST_POISON2  ((void *) 0x00200200)

    #ifndef CONFIG_DEBUG_LIST
    static inline void list_del(struct list_head *entry)
    {
        __list_del(entry->prev, entry->next);
        entry->next = LIST_POISON1;
        entry->prev = LIST_POISON2;
    }
    #else
    extern void list_del(struct list_head *entry);
    #endif

    /**
    * list_replace - replace old entry by new one
    * @old : the element to be replaced
    * @new : the new element to insert
    *
    * If @old was empty, it will be overwritten.
    */

    将old替换为new
    static inline void list_replace(struct list_head *old,
                    struct list_head *new)
    {
        new->next = old->next;
        new->next->prev = new;
        new->prev = old->prev;
        new->prev->next = new;
    }

    将old替换为new,并且将old重新初始化

    static inline void list_replace_init(struct list_head *old,
                        struct list_head *new)
    {
        list_replace(old, new);
        INIT_LIST_HEAD(old);
    }

    /**
    * list_del_init - deletes entry from list and reinitialize it.
    * @entry: the element to delete from the list.
    */

    从链表中删除entry,并且将entry重新初始化
    static inline void list_del_init(struct list_head *entry)
    {
        __list_del(entry->prev, entry->next);
        INIT_LIST_HEAD(entry);
    }

    /**
    * list_move - delete from one list and add as another's head
    * @list: the entry to move
    * @head: the head that will precede our entry
    */

    image

    将list从原来的链表移动到head链表中
    static inline void list_move(struct list_head *list, struct list_head *head)
    {
        __list_del(list->prev, list->next);
        list_add(list, head);
    }

    /**
    * list_move_tail - delete from one list and add as another's tail
    * @list: the entry to move
    * @head: the head that will follow our entry
    */

    image

    将list从原先的链表中删除,添加到head链表中(并且查到head的前边)
    static inline void list_move_tail(struct list_head *list,
                      struct list_head *head)
    {
        __list_del(list->prev, list->next);
        list_add_tail(list, head);
    }

    /**
    * list_is_last - tests whether @list is the last entry in list @head
    * @list: the entry to test
    * @head: the head of the list
    */

    image

    判断list是不是链表head的尾结点
    static inline int list_is_last(const struct list_head *list,
                    const struct list_head *head)
    {
        return list->next == head;
    }

    /**
    * list_empty - tests whether a list is empty
    * @head: the list to test.
    */

    image
    static inline int list_empty(const struct list_head *head)
    {
        return head->next == head;
    }

    /**
    * list_empty_careful - tests whether a list is empty and not being modified
    * @head: the list to test
    *
    * Description:
    * tests whether a list is empty _and_ checks that no other CPU might be
    * in the process of modifying either member (next or prev)
    *
    * NOTE: using list_empty_careful() without synchronization
    * can only be safe if the only activity that can happen
    * to the list entry is list_del_init(). Eg. it cannot be used
    * if another CPU could re-list_add() it.
    */

    image
    static inline int list_empty_careful(const struct list_head *head)
    {
        struct list_head *next = head->next;
        return (next == head) && (next == head->prev);
    }

    /**
    * list_is_singular - tests whether a list has just one entry.
    * @head: the list to test.
    */

    image
    static inline int list_is_singular(const struct list_head *head)
    {
        return !list_empty(head) && (head->next == head->prev);
    }

    static inline void __list_cut_position(struct list_head *list,
            struct list_head *head, struct list_head *entry)
    {
        struct list_head *new_first = entry->next;
        list->next = head->next;
        list->next->prev = list;
        list->prev = entry;
        entry->next = list;
        head->next = new_first;
        new_first->prev = head;
    }

    /**
    * list_cut_position - cut a list into two
    * @list: a new list to add all removed entries
    * @head: a list with entries
    * @entry: an entry within head, could be the head itself
    *    and if so we won't cut the list
    *
    * This helper moves the initial part of @head, up to and
    * including @entry, from @head to @list. You should
    * pass on @entry an element you know is on @head. @list
    * should be an empty list or a list you do not care about
    * losing its data.
    *
    */
    static inline void list_cut_position(struct list_head *list,
            struct list_head *head, struct list_head *entry)
    {
        if (list_empty(head))
            return;
        if (list_is_singular(head) &&
            (head->next != entry && head != entry))
            return;
        if (entry == head)
            INIT_LIST_HEAD(list);
        else
            __list_cut_position(list, head, entry);
    }

    static inline void __list_splice(const struct list_head *list,
                     struct list_head *prev,
                     struct list_head *next)
    {
        struct list_head *first = list->next;
        struct list_head *last = list->prev;

        first->prev = prev; 
          prev->next = first;

        last->next = next;
          next->prev = last;
    }

    /**
    * list_splice - join two lists, this is designed for stacks
    * @list: the new list to add.
    * @head: the place to add it in the first list.
    */

    image

    将链表list中除了结点list在外(去头)的剩余的结点加入到head链表后面。 
    static inline void list_splice(const struct list_head *list,
                    struct list_head *head)
    {
        if (!list_empty(list))
            __list_splice(list, head, head->next);
    }

    /**
    * list_splice_tail - join two lists, each list being a queue
    * @list: the new list to add.
    * @head: the place to add it in the first list.
    */

    image
    static inline void list_splice_tail(struct list_head *list,
                    struct list_head *head)
    {
        if (!list_empty(list))
            __list_splice(list, head->prev, head);
    }

    /**
    * list_splice_init - join two lists and reinitialise the emptied list.
    * @list: the new list to add.
    * @head: the place to add it in the first list.
    *
    * The list at @list is reinitialised
    */

    image

    同时将list重新初始化,

    image

     
    static inline void list_splice_init(struct list_head *list,
                        struct list_head *head)
    {
        if (!list_empty(list)) {
            __list_splice(list, head, head->next);
            INIT_LIST_HEAD(list);
        }
    }

    /**
    * list_splice_tail_init - join two lists and reinitialise the emptied list
    * @list: the new list to add.
    * @head: the place to add it in the first list.
    *
    * Each of the lists is a queue.
    * The list at @list is reinitialised
    */

    image

    同时将list重新初始化,

    image
    static inline void list_splice_tail_init(struct list_head *list,
                         struct list_head *head)
    {
        if (!list_empty(list)) {
            __list_splice(list, head->prev, head);
            INIT_LIST_HEAD(list);
        }
    }

    /**
    * container_of - cast a member of a structure out to the containing structure
    * @ptr:    the pointer to the member.
    * @type:    the type of the container struct this is embedded in.
    * @member:    the name of the member within the struct.
    *
    */
    #define container_of(ptr, type, member) ({           
        const typeof( ((type *)0)->member ) *__mptr = (ptr);   
        (type *)( (char *)__mptr - offsetof(type,member) );})

    /**
    * list_entry - get the struct for this entry
    * @ptr:    the &struct list_head pointer.
    * @type:    the type of the struct this is embedded in.
    * @member:    the name of the list_struct within the struct.
    */

    image


    #define list_entry(ptr, type, member)
        container_of(ptr, type, member)

    /**
    * list_first_entry - get the first element from a list
    * @ptr:    the list head to take the element from.
    * @type:    the type of the struct this is embedded in.
    * @member:    the name of the list_struct within the struct.
    *
    * Note, that list is expected to be not empty.
    */
    #define list_first_entry(ptr, type, member)
        list_entry((ptr)->next, type, member)

    /**
    * list_for_each    -    iterate over a list
    * @pos:    the &struct list_head to use as a loop cursor.
    * @head:    the head for your list.
    */

    prefetch的使用可以参考:

    http://www.cnblogs.com/pengdonglin137/p/3716883.html

    http://www.cnblogs.com/pengdonglin137/p/3716889.html


    #define list_for_each(pos, head)
        for (pos = (head)->next; prefetch(pos->next), pos != (head);
                pos = pos->next)

       1:  struct fox{
       2:      unsigned long tail_length;
       3:      unsigned long weight;
       4:      bool          is_fantastic;
       5:      struct list_head list;
       6:  };
       7:   
       8:  struct fox a;
       9:  struct list_head *p = NULL;
      10:  struct list_head *q = NULL;
      11:   
      12:  ......
      13:  假设a是头结点
      14:   
      15:  q = &(a.list);
      16:   
      17:  list_for_each(p, q)
      18:  {
      19:      ......// 使用指针p完成一些操作
      20:  }

    /**
    * __list_for_each    -    iterate over a list
    * @pos:    the &struct list_head to use as a loop cursor.
    * @head:    the head for your list.
    *
    * This variant differs from list_for_each() in that it's the
    * simplest possible list iteration code, no prefetching is done.
    * Use this for code that knows the list to be very short (empty
    * or 1 entry) most of the time.
    */

    正向遍历head链表,在循环中不能释放pos指向的结点所在的空间


    #define __list_for_each(pos, head)
        for (pos = (head)->next; pos != (head); pos = pos->next)

    示例:

       1:  struct fox{
       2:      unsigned long tail_length;
       3:      unsigned long weight;
       4:      bool          is_fantastic;
       5:      struct list_head list;
       6:  };
       7:   
       8:  struct fox a;
       9:  struct list_head *p = NULL;
      10:  struct list_head *q = NULL;
      11:   
      12:  ......
      13:  假设a是头结点
      14:   
      15:  q = &(a.list);
      16:   
      17:  __list_for_each(p, q)
      18:  {
      19:      ......// 使用指针p完成一些操作
      20:  }

    /**
    * list_for_each_prev    -    iterate over a list backwards
    * @pos:    the &struct list_head to use as a loop cursor.
    * @head:    the head for your list.
    */

    反向遍历head链表,再循环中不能释放pos指向的结点所在的空间
    #define list_for_each_prev(pos, head)
        for (pos = (head)->prev; prefetch(pos->prev), pos != (head);
                pos = pos->prev)

    示例:

       1:  struct fox{
       2:      unsigned long tail_length;
       3:      unsigned long weight;
       4:      bool          is_fantastic;
       5:      struct list_head list;
       6:  };
       7:   
       8:  struct fox a;
       9:  struct list_head *p = NULL;
      10:  struct list_head *q = NULL;
      11:   
      12:  ......
      13:  假设a是头结点
      14:   
      15:  q = &(a.list);
      16:   
      17:  list_for_each_prev(p, q)
      18:  {
      19:      ......// 使用指针p完成一些操作,但是不要释放p指向的结点所站的空间
      20:  }

    /**
    * list_for_each_safe - iterate over a list safe against removal of list entry
    * @pos:    the &struct list_head to use as a loop cursor.
    * @n:        another &struct list_head to use as temporary storage
    * @head:    the head for your list.
    */

    正向遍历head链表,跟list_for_each不同之处是,可以在循环中释放pos指向的结点
    #define list_for_each_safe(pos, n, head)
        for (pos = (head)->next, n = pos->next; pos != (head);
            pos = n, n = pos->next)

    示例:

       1:  struct fox{
       2:      unsigned long tail_length;
       3:      unsigned long weight;
       4:      bool          is_fantastic;
       5:      struct list_head list;
       6:  };
       7:   
       8:  struct fox a;
       9:  struct list_head *p = NULL;
      10:  struct list_head *q = NULL;
      11:   
      12:  ......
      13:  假设a是头结点
      14:   
      15:  q = &(a.list);
      16:   
      17:  struct list_head *n = NULL;
      18:   
      19:  list_for_each_safe(p, n, q)
      20:  {
      21:      ......// 使用指针p完成一些操作,可以删除p指向的结点所在的空间
      22:  }

    /**
    * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
    * @pos:    the &struct list_head to use as a loop cursor.
    * @n:        another &struct list_head to use as temporary storage
    * @head:    the head for your list.
    */

    反向遍历head链表,跟list_for_each_prev不同之处是,可以在循环中释放pos指向的结点

    #define list_for_each_prev_safe(pos, n, head)
        for (pos = (head)->prev, n = pos->prev;
             prefetch(pos->prev), pos != (head);
             pos = n, n = pos->prev)

    示例:

       1:  struct fox{
       2:      unsigned long tail_length;
       3:      unsigned long weight;
       4:      bool          is_fantastic;
       5:      struct list_head list;
       6:  };
       7:   
       8:  struct fox a;
       9:  struct list_head *p = NULL;
      10:  struct list_head *q = NULL;
      11:   
      12:  ......
      13:  假设a是头结点
      14:   
      15:  q = &(a.list);
      16:   
      17:  struct list_head *n = NULL;
      18:   
      19:  list_for_each_prev_safe(p, n, q)
      20:  {
      21:      ......// 使用指针p完成一些操作,可以删除p指向的结点所在的空间
      22:  }

    /**
    * list_for_each_entry    -    iterate over list of given type
    * @pos:    the type * to use as a loop cursor.
    * @head:    the head for your list.
    * @member:    the name of the list_struct within the struct.
    */

    正向遍历head链表,与list_for_each不同之处是,pos指向的可以不是struct list_head类型的结构体,而是含有struct

    list_head类型结构体的结构体。
    #define list_for_each_entry(pos, head, member)               
        for (pos = list_entry((head)->next, typeof(*pos), member);   
             prefetch(pos->member.next), &pos->member != (head);    
             pos = list_entry(pos->member.next, typeof(*pos), member))

    示例:

       1:  struct fox{
       2:      unsigned long tail_length;
       3:      unsigned long weight;
       4:      bool          is_fantastic;
       5:      struct list_head 
    list
    ;
       6:  };
       7:   
       8:  struct fox a;
       9:  struct fox *p = NULL;
      10:  struct head_list *q = NULL;
      11:  ......
      12:  假设a是头结点
      13:   
      14:  q = &(a.list);
      15:   
      16:  list_for_each_entry(p, q, 
    list
    )  // 其中list是struct fox中struct list_head类型的成员变量名
      17:  {
      18:      ......// 使用指针p完成一些操作,不可以释放p指向的结点所在的空间
      19:  }

    /**
    * list_for_each_entry_reverse - iterate backwards over list of given type.
    * @pos:    the type * to use as a loop cursor.
    * @head:    the head for your list.
    * @member:    the name of the list_struct within the struct.
    */

    正向遍历head链表,与list_for_each_prev不同之处是,pos指向的可以不是struct list_head类型的结构体,而是含有struct list_head类型结构体的结构体。

    #define list_for_each_entry_reverse(pos, head, member)           
        for (pos = list_entry((head)->prev, typeof(*pos), member);   
             prefetch(pos->member.prev), &pos->member != (head);    
             pos = list_entry(pos->member.prev, typeof(*pos), member))

    示例:

       1:  struct fox{
       2:      unsigned long tail_length;
       3:      unsigned long weight;
       4:      bool          is_fantastic;
       5:      struct list_head list;
       6:  };
       7:   
       8:  struct fox a;
       9:  struct fox *p = NULL;
      10:  struct head_list *q = NULL;
      11:  ......
      12:  假设a是头结点
      13:   
      14:  q = &(a.list);
      15:   
      16:  list_for_each_entry_reverse(p, q, list)  // 其中list是struct fox中struct list_head类型的成员变量名
      17:  {
      18:      ......// 使用指针p完成一些操作,不可以释放p指向的结点所在的空间
      19:  }

    /**
    * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
    * @pos:    the type * to use as a start point
    * @head:    the head of the list
    * @member:    the name of the list_struct within the struct.
    *
    * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
    */
    #define list_prepare_entry(pos, head, member)
        ((pos) ? : list_entry(head, typeof(*pos), member))

    /**
    * list_for_each_entry_continue - continue iteration over list of given type
    * @pos:    the type * to use as a loop cursor.
    * @head:    the head for your list.
    * @member:    the name of the list_struct within the struct.
    *
    * Continue to iterate over list of given type, continuing after
    * the current position.
    */
    #define list_for_each_entry_continue(pos, head, member)        
        for (pos = list_entry(pos->member.next, typeof(*pos), member);   
             prefetch(pos->member.next), &pos->member != (head);   
             pos = list_entry(pos->member.next, typeof(*pos), member))

    /**
    * list_for_each_entry_continue_reverse - iterate backwards from the given point
    * @pos:    the type * to use as a loop cursor.
    * @head:    the head for your list.
    * @member:    the name of the list_struct within the struct.
    *
    * Start to iterate over list of given type backwards, continuing after
    * the current position.
    */
    #define list_for_each_entry_continue_reverse(pos, head, member)       
        for (pos = list_entry(pos->member.prev, typeof(*pos), member);   
             prefetch(pos->member.prev), &pos->member != (head);   
             pos = list_entry(pos->member.prev, typeof(*pos), member))

    /**
    * list_for_each_entry_from - iterate over list of given type from the current point
    * @pos:    the type * to use as a loop cursor.
    * @head:    the head for your list.
    * @member:    the name of the list_struct within the struct.
    *
    * Iterate over list of given type, continuing from current position.
    */
    #define list_for_each_entry_from(pos, head, member)            
        for (; prefetch(pos->member.next), &pos->member != (head);   
             pos = list_entry(pos->member.next, typeof(*pos), member))

    /**
    * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
    * @pos:    the type * to use as a loop cursor.
    * @n:        another type * to use as temporary storage
    * @head:    the head for your list.
    * @member:    the name of the list_struct within the struct.
    */
    #define list_for_each_entry_safe(pos, n, head, member)           
        for (pos = list_entry((head)->next, typeof(*pos), member),   
            n = list_entry(pos->member.next, typeof(*pos), member);   
             &pos->member != (head);                    
             pos = n, n = list_entry(n->member.next, typeof(*n), member))

    /**
    * list_for_each_entry_safe_continue
    * @pos:    the type * to use as a loop cursor.
    * @n:        another type * to use as temporary storage
    * @head:    the head for your list.
    * @member:    the name of the list_struct within the struct.
    *
    * Iterate over list of given type, continuing after current point,
    * safe against removal of list entry.
    */
    #define list_for_each_entry_safe_continue(pos, n, head, member)        
        for (pos = list_entry(pos->member.next, typeof(*pos), member),        
            n = list_entry(pos->member.next, typeof(*pos), member);       
             &pos->member != (head);                       
             pos = n, n = list_entry(n->member.next, typeof(*n), member))

    /**
    * list_for_each_entry_safe_from
    * @pos:    the type * to use as a loop cursor.
    * @n:        another type * to use as temporary storage
    * @head:    the head for your list.
    * @member:    the name of the list_struct within the struct.
    *
    * Iterate over list of given type from current point, safe against
    * removal of list entry.
    */
    #define list_for_each_entry_safe_from(pos, n, head, member)            
        for (n = list_entry(pos->member.next, typeof(*pos), member);       
             &pos->member != (head);                       
             pos = n, n = list_entry(n->member.next, typeof(*n), member))

    /**
    * list_for_each_entry_safe_reverse
    * @pos:    the type * to use as a loop cursor.
    * @n:        another type * to use as temporary storage
    * @head:    the head for your list.
    * @member:    the name of the list_struct within the struct.
    *
    * Iterate backwards over list of given type, safe against removal
    * of list entry.
    */
    #define list_for_each_entry_safe_reverse(pos, n, head, member)       
        for (pos = list_entry((head)->prev, typeof(*pos), member),   
            n = list_entry(pos->member.prev, typeof(*pos), member);   
             &pos->member != (head);                    
             pos = n, n = list_entry(n->member.prev, typeof(*n), member))

    /*
    * Double linked lists with a single pointer list head.
    * Mostly useful for hash tables where the two pointer list head is
    * too wasteful.
    * You lose the ability to access the tail in O(1).
    */

    struct hlist_head {
        struct hlist_node *first;
    };

    struct hlist_node {
        struct hlist_node *next, **pprev;
    };

    #define HLIST_HEAD_INIT { .first = NULL }
    #define HLIST_HEAD(name) struct hlist_head name = {  .first = NULL }
    #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
    static inline void INIT_HLIST_NODE(struct hlist_node *h)
    {
        h->next = NULL;
        h->pprev = NULL;
    }

    static inline int hlist_unhashed(const struct hlist_node *h)
    {
        return !h->pprev;
    }

    static inline int hlist_empty(const struct hlist_head *h)
    {
        return !h->first;
    }

    static inline void __hlist_del(struct hlist_node *n)
    {
        struct hlist_node *next = n->next;
        struct hlist_node **pprev = n->pprev;
        *pprev = next;
        if (next)
            next->pprev = pprev;
    }

    static inline void hlist_del(struct hlist_node *n)
    {
        __hlist_del(n);
        n->next = LIST_POISON1;
        n->pprev = LIST_POISON2;
    }

    static inline void hlist_del_init(struct hlist_node *n)
    {
        if (!hlist_unhashed(n)) {
            __hlist_del(n);
            INIT_HLIST_NODE(n);
        }
    }

    static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
    {
        struct hlist_node *first = h->first;
        n->next = first;
        if (first)
            first->pprev = &n->next;
        h->first = n;
        n->pprev = &h->first;
    }

    /* next must be != NULL */
    static inline void hlist_add_before(struct hlist_node *n,
                        struct hlist_node *next)
    {
        n->pprev = next->pprev;
        n->next = next;
        next->pprev = &n->next;
        *(n->pprev) = n;
    }

    static inline void hlist_add_after(struct hlist_node *n,
                        struct hlist_node *next)
    {
        next->next = n->next;
        n->next = next;
        next->pprev = &n->next;

        if(next->next)
            next->next->pprev  = &next->next;
    }

    /*
    * Move a list from one list head to another. Fixup the pprev
    * reference of the first entry if it exists.
    */
    static inline void hlist_move_list(struct hlist_head *old,
                       struct hlist_head *new)
    {
        new->first = old->first;
        if (new->first)
            new->first->pprev = &new->first;
        old->first = NULL;
    }

    #define hlist_entry(ptr, type, member) container_of(ptr,type,member)

    #define hlist_for_each(pos, head)
        for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; });
             pos = pos->next)

    #define hlist_for_each_safe(pos, n, head)
        for (pos = (head)->first; pos && ({ n = pos->next; 1; });
             pos = n)

    /**
    * hlist_for_each_entry    - iterate over list of given type
    * @tpos:    the type * to use as a loop cursor.
    * @pos:    the &struct hlist_node to use as a loop cursor.
    * @head:    the head for your list.
    * @member:    the name of the hlist_node within the struct.
    */
    #define hlist_for_each_entry(tpos, pos, head, member)            
        for (pos = (head)->first;                    
             pos && ({ prefetch(pos->next); 1;}) &&            
            ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;});
             pos = pos->next)

    /**
    * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
    * @tpos:    the type * to use as a loop cursor.
    * @pos:    the &struct hlist_node to use as a loop cursor.
    * @member:    the name of the hlist_node within the struct.
    */
    #define hlist_for_each_entry_continue(tpos, pos, member)        
        for (pos = (pos)->next;                        
             pos && ({ prefetch(pos->next); 1;}) &&            
            ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;});
             pos = pos->next)

    /**
    * hlist_for_each_entry_from - iterate over a hlist continuing from current point
    * @tpos:    the type * to use as a loop cursor.
    * @pos:    the &struct hlist_node to use as a loop cursor.
    * @member:    the name of the hlist_node within the struct.
    */
    #define hlist_for_each_entry_from(tpos, pos, member)            
        for (; pos && ({ prefetch(pos->next); 1;}) &&            
            ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;});
             pos = pos->next)

    /**
    * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
    * @tpos:    the type * to use as a loop cursor.
    * @pos:    the &struct hlist_node to use as a loop cursor.
    * @n:        another &struct hlist_node to use as temporary storage
    * @head:    the head for your list.
    * @member:    the name of the hlist_node within the struct.
    */
    #define hlist_for_each_entry_safe(tpos, pos, n, head, member)         
        for (pos = (head)->first;                    
             pos && ({ n = pos->next; 1; }) &&                 
            ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;});
             pos = n)

    #endif

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  • 原文地址:https://www.cnblogs.com/pengdonglin137/p/3712201.html
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